1. Field of the Invention
This invention relates to a positioning system for accurately setting anchor bolts in concrete casting of foundations. More particularly, the invention is directed to a threaded flange disposed on the anchor bolt next to the inner surface of a formwork template. The flange cooperates with a threaded, closed-end sleeve which has a flange on its inner end to firmly position the anchor bolt in a perpendicular relationship to the template inner surface during pouring and setting of the concrete to insure that the anchor bolt will extend outwardly at right angles to the concrete surface.
2. Description of Related Art
Devices for positioning anchor elements during concrete casting are described in U.S. Pat. Nos. 4,383,674 and 4,383,675. However, the core bodies disclosed in these patents are complex, and are primarily intended to form a recess in the concrete member to receive the eye portion of an anchor element used to haul the concrete member into position for concrete construction work. There is no critical need that the anchor bolt itself be perpendicular to the outer surface of the formed concrete body, and no mention is made of such purpose or intent.
U.S. Pat. No. 4,408,940 is directed to a bolt anchor assembly having a hollow tubular portion and a base plate. The anchor bolt is disposed inside the tubular member, and both the base plate and the tubular member remain embedded in the concrete after the anchor bolt is set. The main purpose of the sleeve, or tubular portion, is to provide allowance for lateral movement of the bolt to accommodate variations in location when anchoring heavy machinery to the concrete floor.
U.S. Pat. No. 4,781,006 describes a chord bar connector system for prefabricated concrete wall construction panels which are intended to be earthquake-proof. The casting system includes removable inserts to form notches for access to the chord bars to interconnect adjacent building panels. The chord bar connector is a positioning means for the chord bars, but it remains in the cast concrete panel.
An injection molded, internally threaded plastic cap or sleeve is shown in FIGS. 11.11, 11.12, and 11.13 of INJECTION MOULD DESIGN, authored by R.G.W. Pye, 2d Edition, Plastics & Rubber Institute, 1978. However, the cap or sleeve disclosed there has no perpendicular flange at its open end.